1. Field of the Invention
This invention relates to a recording device and a recording method which perform recording on a recording medium.
Here, as the recording device to which the present invention has been applied, there may be included those taking form of copying device, Japanese word processer having key inputting machine, electronic typewriter and further facscimile device having sending and receiving functions in combination with printer, reader, etc. to be used as the image output terminal of information processing machines such as computers, etc. As the recording system, there may be included, for example, the so called heat transfer recording system, heat-sensitive recording system and ink jet recording system (for example, the so called bubble jet recording system or recording system by use of piezoelectric element), etc.
2. Related Background Art
In the prior art, in a recording device of the dot recording system, recording scanning is generally performed with a recording head capable of dot recording of about 24 dots.
When the recording dot number in one row is made a number exceeding 100 for enhancing recording speed, the driving circuits for driving the recording sections corresponding to these dots are also required in number corresponding to the dots. As the result, the drive circuit as a whole becomes larger, leading to elevation in cost, enlargement of machines. For solving this problem, it may be conceivable to divide the recording head section into blocks, driving the respective recording sections divided into blocks by time division, thereby reducing the dot number driven at the same time by the drive circuit.
FIG. 1A shows the block division contents of a liquid jet recording head of the prior art.
In FIG. 1A, 128 discharge openings are divided into 16 blocks and the recording sections 101 to 116 of 16 blocks are arrayed in one row. Accordingly, each recording section has ink discharge openings corresponding to 8 dots as shown in FIG. 1B. Such recording sections 101-116 are driven by time division, and 8 dots are dot recorded at the same time. When ink is discharged through all the discharge openings by moving the recording in the main scanning direction at a constant speed, the interval from the recorded image of the first block to the recorded image of the 16th block becomes approximately 60 .mu.m when the recording density is set at 400 DPI (dot/inch) (FIG. 1C).
Further, the dot interval between adjacent blocks is 4 .mu.m which is as large as corresponding to the size of about one picture element. Accordingly, for making smaller the slippage of recording dots by such time division recording, the recording head is located obliquely as shown in FIG. 2A for carrying out recording scanning. And, as shown in FIG. 2B, it has been proposed to perform recording of the respective dot rows in one row by tolerating only slanting of the dot rows of the respective blocks. The block actuation order at this time is shown in FIG. 3. The arrowhead A shows the main scanning direction (going way direction) of the recording head and the arrowhead B slanted angle.
However, in the recording device of this kind of the prior art, for increasing the speed of recording or obtaining mirror image, returning way recording may be sometimes practiced. In this case, in the recording device of the prior art, since the block driving order is the same as in the going way when the recording head is mainly scanned in the direction by the arrowhead A in FIG. 4A (returning way recording), there was the problem to be solved that the slippage of the recorded image became further greater as shown in FIG. 4B. The arrowhead C indicates the sub-scanning direction.
Further, there was the task to be solved as described below.
For example, in a heat-transfer color printer, it remains necessary to repeat printing for each of the different colored ink ribbons used. In such constitution, since there is no simultaneous driving of a plurality of colors (writing heads), no much result can be expected even if printing speed may be desired to be increased.
Whereas, in a carriage having the respective writing heads of cyan, magenta, yellow and black mounted thereon, image recording becomes possible while performing writing simultaneously, namely corresponding to one scan by one movement. In this case, since there are physical intervals between the respective writing heads, the corresponding delay processing is required.
It is necessary to provide intervals between the heads because these cannot be avoided in constitution. Besides, the head interval, in the case of a printer having a printing density of 400 dpi, will result in color slippage of 1.5 picture elements or more by 100 .mu.m slippage.
In recording natural picture, this is evidently a vital trouble.
In the prior art, for the purpose of correcting such physical interval, RAM's have been employed to form time difference between writing and reading of data.
However, in this case, there ensue the problems as shown below.
(1) Independent RAM's for respective colors must be provided.
(2) Since in RAM with large capacity of low cost has many byte units, the circuit becomes complicated for converting one bit serial data of multi-color to byte data of separate colors.
And, from these problems, the troubles of enlargement and increased cost of the device have been caused to occur.
Further, there has been the task to be solved as described below.
Ordinarily, for example, in a color ink jet printer, there is no substantial difference in printing speed between color printing and monocolor printing.
For increasing the speed, the image clock rate may be increased, but since the driving speed of the writing head for ink jet is limited, no such measure can be taken.
If the driving speed of the writing head for ink jet is increased to a certain value or higher, there will ensue such troubles that the life of the writing head becomes markedly short or that the printing quality is deteriorated.
However, on the other hand, there is in fact a great need that printing speed or copying speed is desired to be made more rapid in monochromatic printing or monochromatic copying (e.g. conventional black color printing).
This may be said to be a requirement as a matter of course in view of high speed printer such as plain paper copying machine under the present situation and LBP (laser beam printer).
Further, there have been the problems to be solved as described below. The tasks to be described below is undischarging in the ink jet recording system. As the countermeasures for the undischarging problem, there have been invented:
(A) the blank discharge actuation which discharges ink compulsorily ink at predetermined timing;
(B) the absorbing actuation which absorbs compulsorily ink at predetermined timing.
In the present invention, of the above-mentioned two items, the former blank discharge actuation is to be described. When performing blank discharge actuation, there are the following problems:
(A) the circuit scale for forming blank discharge data becomes larger to bring about cost-up;
(B) when blank discharge data are formed by CPU (central processing unit), because of considerably large amount of blank discharge data, it takes too much time for data formation, whereby the speed of the printer is lowered.